All right, this is going to sound kind of crazy--but have you tried pennies? We have six cats and some of them like the treats, some of them like Da Bird, some of them like the catnip toys--but Slipper likes pennies. We slide a penny across the floor and she will chase it for almost half an hour, batting it away as she reaches it and it takes a while for her to lose her interest. Maybe try something like that?
Casper hasn't been around long enough for this, yet. In the summer when the weather was hot, I used to give Spike an ice cube and let him bat it around on the kitchen floor. A partially melted ice cube will skate for a mile across a linoleum floor!
(Water on the floor from a melted ice cube only amounts to a couple of tablespoons full of water.)
I got my lazy cat to exercise more by getting him a kitten. They tear around the house and currently are having a lot of fun with paper packing material.
I have also found da bird to be effective and taking him outside for walks.
Thank you everybody for all the info and links. Xena definitely needs some exercise. Standing for food is about the only exercise she gets. She also has a bit of a limp and I don't wish to aggravate that.
I leash trained my cats and take them for walks. There's no reason why a cat can't go to the park for some walk and playtime. The cats love it and I enjoy being able to do things with them out of the house.
Leash training would be fun. My boy likes things that move quickly, and my daughters are learning to move the toys quickly. He loses interest at times and easily distracted lol